I am currently in lock down with 5 runner duck eggs. I started with 6 but it showed no signs of fertility when candled at 10 days. The remaining eggs all showed normal signs throughout. I stopped turning at day 25. It is now day 28 and there are no signs of pipping or movement. Should I attempt to candle and see if I can see movement inside. This is my first time. Many thanks in advance.

I doubt you will see any movement Moonwillow if you candled now- just a black mass and you may disorientate any chicks manoeuvring to pip. If your incubation temperature was a tiny fraction low the hatch can be delayed by a day, or longer if the error was greater. This all depends on your machine. If the air sack hasn't developed because the incubation humidity was too high the chick won't be able to manoeuvre to pip. I'd wait at least 3 more days anyway.